Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Consider the following relational schema: Doctor(DName,Reg_no) Patient(Pname, Disease) Assigned_To (Pname,Dname) Give expression in both Tuple calculus and Domain calculus for every of the queries:(i) Get the names of patients who are assigned to more than one doctor. (ii) Get the names of doctors who are treating patients with ‘Polio'.
Ans: (i)Tuple Calculus: {p[PName] | p ∈ PATIENT ∧ ∃a1, a2 (a1 ∈ ASSIGNED_TO ∧ a2 ∈ ASSIGNED_TO ∧p[PName] = a1[PName] ∧ a1[PName] = a2[PName] ∧ a1[DName] ≠ a2[DName])} Domain Calculus:{p | ∃p1, d1, p2, d2 (
∈ PATIENT ∧ ∈ ASSIGNED_TO ∧ ∈ASSIGNED_TO ∧ p1 = p2 ∧ d1 ≠ d2)} (ii)Tuple Calculus: {u[Dname] | u ∈ ASSIGNED_TO ∧ ∃t (t ∈ PATIENT ∧ t[Disease] = ‘Polio' ∧t[PName] = u[PName])} Domain Calculus: {d | ∃p1, p2, s2 ( ∈ ASSIGNED_TO ∧ ∈ PATIENT∧ p1 = p2 ∧ s2 = ‘Polio')}
Draw an Entity-Relationship model for the relational schema given in the Appendix. Show all the entities, relationships, relationship names, and attributes and also underline the
how to operate database in access ?
# ???? ..
What are the different approaches for database design? There are two basic approaches for database design which are as follows: Attribute driven: It compiles a list of att
Create a new user : CREATE USER IDENTIFIED BY Example: //CREATE USER MCA12 IDENTIFIED BY W123 Grant: It is used to give database access permission to users. It is of
By using the delete operation some consisting records can be deleted from a relation. To delete some definite records from the database a condition is also specified based on which
i have a homework assignment identical to one you have listed
Clustering Indexes It may be an excellent idea to keep data of the students in the order of the programme they have registered as most of the data file accesses may need studen
client server architeutre
Find out the names and company names of all employees sorted in ascending order of company name and descending order of employee names of by which company. SELECT EMPLOYEE_NAME,
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd